This invention related in general to work-producing reciprocating engines and, more specifically, to a reciprocating engine in which gas expansion work is performed by ion repulsion.
Reciprocating engines in which internal combustion of a fuel/air mixture in the volume between a cylinder head and a moving piston generates forces on the piston by gas expansion have long been in use and have reached a high state of development. Such engines are mechanically sturdy and long lived and can be rapidly and economically manufactured. Until recently, such internal combustion reciprocating engines were considered to be the optimum for many purposes, such as in powering automobiles and trucks.
The internal combustion engine converts the chemical energy of the fuel to heat which generates pressure to perform work in accordance with the well-known gas laws. However, heat, being generally recognized as the lowest form of energy, introduces large unavoidable energy losses through the exhaust gases and the engine cooling means. The energy conversion efficiency of such engines is usually much less than 40%. Until recently such internal combustion reciprocating engines were considered to be quite satisfactory for many purposes, such as in the powering of automobiles and trucks.
Recently, however, additional shortcomings of the internal combustion engine have become apparent as concern over air pollution has increased. The need for additives such as tetraethyl lead to increase octane ratings has introduced a considerable amount of lead into the atmosphere. Unburned hydrocarbons and other agents such as nitrous oxides are also emitted by internal combustion engines. Because of the types of fuels used, often mixtures of hydrocarbons and other agents, and the high temperatures of combustion, many of the pollutants in the engine exhaust are difficult to control. The addition of emission controls to the engine causes a considerable additional loss in energy conversion efficiency and units such as catalytic converters may even themselves be sources of additional pollutants.
The rising cost and probable shortages of oil-derived fuels for internal-combustion engines are becoming increasingly important. The use of fuels, such as hydrogen produced by the disassociation of water or alcohols derived from organic materials may become necessary.
Ionization of fuel introduced into internal combustion engines has been proposed in U.S. Pat. No. 2,766,582 as a technique for improving engine efficiency. Apparently, ionization of the air/fuel mixture in the cylinder is induced by an imposed voltage. While this may produce a slight increase in cylinder pressure and slightly better mixing of fuel and air, all of the fuel consumption and air pollution problems of internal combustion engines remain.
Attempts have been made to develop alternative engines which would be less polluting, more fuel efficient and less dependent on oil-based fuels. As yet, none of these has been successful in automobile and truck applications.
Fuel cells have been developed in recent years primarily as a source of electrical power. In typical fuel cells, oxygen and a fuel such as hydrogen are introduced into spaced porous catalytic electrodes separated by an electrolyte solution. Electron flow through a conductor connecting the two electrodes occurs as the fuel and oxygen are ionized. The chemical reaction is completed when the ions migrate to each other through the electrolyte. The reaction is cool, since energy had been given up through the work performed by the electrons or current flowing through the conductor to a load. Fuel cells have a number of advantages over internal combustion engines in more complete combustion resulting in less or no polluting emissions and high thermal efficiency. Attempts have been made to operate automobiles with DC motors powered by fuel cells. However, the porous electrodes and electrolytes tend to be short lived and the fuel cells must be excessively large and heavy in order to supply sufficient electrical power to the drive motors. This technology is still in its infancy.
Thus, there is a continuing need for improved engines which can make use of the well-developed body of reciprocating engine technology while providing improved operating efficiency, lower polluting emissions and a wider choice of fuels.